#loop through results of blast
while (<DAT>){
    chomp $_;

    # store tab delimited values into an array
    # btab file is from clean_expand btab.
    my @result = split(/\t/, $_);

    # seq are rRNA positive only if (b.qry_end - b.qry_start) >= 150)
    # AND ((b.qry_start<=20) OR (b.qry_end >= (b.query_length-20)))
    if ( $result[6]-$result[5] >= 150 && ( $result[5] <= 20 || ($result[6] >= ($result[1]-20)) ) ){

      #get rRNA identified sequence.
      push @ident, $result[0];

      $rRNA_positive .= $_ ."\n";
    }
}
close DAT;

# loop through input fasta file
while(<FSA>){
  if ($_ =~ /^>/){
    $flag = 0;
    # loop through all identified seqs and find it in fasta file
    for (my $i=0; $i<$#ident; $i++){
      if ($_ =~ /$ident[$i]/i){
	$idx = $i;
	$flag = 1;
      }
    }

    # once sequence if found remove it from array (reduces subsequent loops)
    if ($flag){
      @ident = @ident[0..$idx-1,$idx+1..$#ident];
    }
  }

  # output to appropriate streams
  if ($flag){
    print rPOS $_;
  } else {
    print rNEG $_;
  }
}

close FSA;
close rPOS;
close rNEG;

# open btab_blast_result to overwrite it with rRNA positive results.
open(OUT, ">", $btab_blast_result) || die $logger->logdie("Could not open file $btab_blast_result");
print OUT $rRNA_positive;
close OUT;